#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MAXN = 100005;
const int INF = 1e17;
vector<pair<int,int>> z[MAXN];
pair<int,int> canh[MAXN];
int high[MAXN];
int low[MAXN];
int check[MAXN];
int up[MAXN][25];
int g[MAXN][25];
int val[MAXN][25];
int sta[MAXN];
int fin[MAXN];
int rev[MAXN];
int tour;
int a, s, q, e;
int down[MAXN][25];
int dis[MAXN];
int fwd[25];
struct node{
pair<int,int> st,nd,rd;
};
node low1[1000000];
void update(int i,int val,int p){
if (val<=low1[i].st.first){
low1[i].rd=low1[i].nd;
low1[i].nd=low1[i].st;
low1[i].st={val,p};
}else if (val<=low1[i].nd.first){
low1[i].rd=low1[i].nd;
low1[i].nd={val,p};
}else if (val<=low1[i].rd.first){
low1[i].rd={val,p};
}
}
void dfs(int i, int par) {
tour++;
sta[i] = tour;
rev[tour] = i;
low[i] = INF;
if (check[i]) {
low[i] = 0;
update(i,0,i);
}
for (auto p : z[i]) {
if (p.first == par) continue;
high[p.first] = high[i] + 1;
dis[p.first] = dis[i] + p.second;
dfs(p.first, i);
update(i,low[p.first]+p.second,p.first);
low[i] = min(low[i], low[p.first] + p.second);
}
fin[i] = tour;
}
void dfs1(int i, int par) {
up[i][0] = par;
for (int j = 1; j <= 20; j++) {
up[i][j] = up[up[i][j - 1]][j - 1];
g[i][j] = g[up[i][j - 1]][j - 1] + g[i][j - 1];
val[i][j] = min(val[i][j - 1], val[up[i][j - 1]][j - 1] + g[i][j - 1]);
down[i][j] = min(down[i][j - 1], down[up[i][j - 1]][j - 1]);
}
int max1 = INF, max2 = INF;
int trace = 0, id = 0;
if (check[i]) {
max1 = 0;
trace = 0;
id = 0;
}
for (auto p : z[i]) {
if (p.first == par) continue;
if (max1 > low[p.first] + p.second) {
max1 = low[p.first] + p.second;
trace = p.first;
id = p.second;
}
}
for (auto p : z[i]) {
if (p.first == par) continue;
if (p.first == trace) continue;
if (max2 > low[p.first] + p.second) {
max2 = low[p.first] + p.second;
}
g[p.first][0] = p.second;
val[p.first][0] = p.second + max1;
down[p.first][0] = max1 + dis[i];
dfs1(p.first, i);
}
if (trace) {
g[trace][0] = id;
val[trace][0] = id + max2;
down[trace][0] = max2 + dis[i];
dfs1(trace, i);
}
}
int lca(int x,int y){
if (high[x]<high[y]){
swap(x,y);
}
for (int i=20;i>=0;i--){
if (high[up[x][i]]>=high[y]){
x=up[x][i];
}
}
// cout << x << " " << y << '\n';
if (x==y){
return x;
}
for (int i=20;i>=0;i--){
if (up[x][i]!=up[y][i] && up[x][i]!=0){
x=up[x][i];
y=up[y][i];
}
}
return up[x][0];
}
int caldis(int x,int y){
if (high[x]<high[y]){
swap(x,y);
}
int cnt=0;
for (int i=20;i>=0;i--){
if (high[up[x][i]]>=high[y]){
cnt+=g[x][i];
x=up[x][i];
}
}
if (x==y){
return cnt;
}
for (int i=20;i>=0;i--){
if (up[x][i]!=up[y][i] && up[x][i]!=0){
cnt+=g[x][i];
cnt+=g[y][i];
x=up[x][i];
y=up[y][i];
}
}
return cnt+g[x][0]+g[y][0];
}
bool check1(int p,int x){
// cout << sta[x] << " " << fin[x] << "\n";
bool req1 = (sta[p] >= sta[x] && sta[p] <= fin[x] && sta[e] >= sta[x] && sta[e] <= fin[x]);
bool req2 = ((sta[p] < sta[x] || sta[p] > fin[x]) && (sta[e] < sta[x] || sta[e] > fin[x]));
return (req1 || req2);
}
signed main() {
// freopen("test.txt", "r", stdin);
// freopen("o2.out", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> a >> s >> q >> e;
fwd[0] = 1;
for (int i = 1; i <= 20; i++) {
fwd[i] = fwd[i - 1] * 2;
}
for (int i = 1; i < a; i++) {
int x, y, t;
cin >> x >> y >> t;
canh[i] = {x, y};
z[x].push_back({y, t});
z[y].push_back({x, t});
}
for (int i = 1; i <= s; i++) {
int x;
cin >> x;
check[x] = 1;
}
for (int i=1;i<=a;i++){
low1[i].st={1e17,1};
low1[i].nd={1e17,1};
low1[i].rd={1e17,1};
}
high[0]=-1;
dfs(e, 0);
dfs1(e, 0);
// for (int i=1;i<=a;i++){
// cout << low[i] << "\n";
// }
while (q--) {
int road, p;
cin >> road >> p;
int x = canh[road].first;
int y = canh[road].second;
int dis1=caldis(x,p);
int dis2=caldis(y,p);
if (dis1>dis2){
swap(x,y);
}
int l=lca(p,x);
int l1=lca(p,y);
// cout << x << " " << p << "\n";
// cout << l << " " << l1 << "\n";
if (l!=x || l1!=y) {
cout << "escaped" << "\n";
continue;
}
int ans=INF;
//cout << sta[x] << " " << sta[p] << "\n";
if (sta[x]<sta[p] || sta[x]>fin[p]){
ans=min(ans,low[p]);
//cout << "ok" << "\n";
}
// cout << ans << "\n";
if (check[p]){
ans=0;
}
int pos1,pos2;
int distance = high[p] - high[l]-1;
int t_node = p;
int cur = 0;
int step = 0;
for (int i = 20; i >= 0; i--) {
if (step + fwd[i] <= distance) {
ans = min(ans, val[t_node][i] + cur);
cur += g[t_node][i];
t_node = up[t_node][i];
step += fwd[i];
}
}
pos1=t_node;
if (pos1==l){
pos1=-1;
}
distance = high[x] - high[l]-1;
t_node = x;
cur = 0;
step = 0;
for (int i = 20; i >= 0; i--) {
if (step + fwd[i] <= distance) {
ans = min(ans, down[t_node][i] -dis[l] + (dis[p]-dis[l]));
t_node = up[t_node][i];
step += fwd[i];
}
}
pos2=t_node;
if (x==l){
pos2=-1;
}
// cout << pos1 << " " << pos2 << "\n";
int preans;
if (low1[l].st.second==pos1 ||low1[l].st.second==pos2 ){
if (low1[l].nd.second==pos1 || low1[l].nd.second==pos2){
// cout << "ok" << "\n";
preans=low1[l].rd.first+dis[p]-dis[l];
}else{
//cout << "ok" << "\n";
preans=low1[l].nd.first+dis[p]-dis[l];
}
}else{
// cout << "ok" << " ";
// cout << low1[l].st.first << "\n";
// cout << "ok" << "\n";
preans=low1[l].st.first+dis[p]-dis[l];
}
// cout << preans << "\n";
ans=min(ans,preans);
if (sta[p]<sta[x] || sta[p]>fin[x]){
int distance = high[1] - high[l];
int t_node = l;
int cur = 0;
int step = 0;
for (int i = 20; i >= 0; i--) {
if (step + fwd[i] <= distance) {
ans = min(ans, val[t_node][i] + cur);
cur += g[t_node][i];
t_node = up[t_node][i];
step += fwd[i];
}
}
}
if (ans>=INF){
cout << "oo" << "\n";
}else{
cout << ans << "\n";
}
}
return 0;
}
/*
freopen("test.txt", "r", stdin);
freopen("o2.out", "w", stdout);
*/
/*
10 3 2 2
1 1 0
1 1 0
0 1 1
1 0 0
1 1 0
1 0 1
1 0 1
1 1 0
0 0 1
0 1 1
0
0
*/
